Method of and apparatus for evaporating liquids



Nov. 27, 1923. M. J. OBOY'LE ET AL METHOD OF AND APPARATUS FOR EVAPORATING LIQUIDS Filed April 13, 1918 Patented Nov. 27,1923.

OFYFI-ICBL MARTIN J. OBOYLE, OF EVELAND. AND EDWARD 0., HOLTON, OF- OLMSTED-FALLS,

OHIO, ASSIGNORS TO *IHE SHERWIN WILLIAMS COMPANY, OF CLEVELAND, OHIO,

- A CORPORATION OF OHIO.

MEIHOD OF AND APPARATUS FOR ETVABORA' IING ,L IQUID S;

Application filed April 12.

To a?! whom, it m (13/ con ccrn lie it known that weyMan'rm J. OBoYLn' and lCnWARn C.. HoILToN. both citizens of the United States. and residents of ('leve a liquid, more particularly directed to a method and apparatus for preventing loss of time caused by shutting down the apparatus to remove deposits formed at vari ous points in theiapparatus. It'hasbeen found in such methods, and in the usual apparatus used for carnving out such methods. that considerable dilricultvis met with from the carrying over into the exhaust conduits of some of thomaterial in the drier. material 50- carried over deposits at some point in the .discharge conduits and blocks these so thatthe apparatus must be opened frequently for cleaning, causing a very material reduction in the available operating time 'of the apparatus. Mate-rial has also been'found. to deposit at other points, which will be hereinafter pointed out, with greatdctriment to continuous and efiicient operation. It one object of the present invention to avoid these difficulties by themethods and the apparatus which i will be hereinafter described. To the accomplishment of the' foregoing and related ends, said'invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain means and one mode of carryin out the invention, such disclosed means an mode illustrating, howeverbut one of various. Ways in which the principle of the invention may *be used.

In said annexed drawingsy- Fig. 1 is' a side-elevation, artiaily in transverse section, through a 'rier, shown .more or less 191s. seri i nb; 228.1 6.

I anniatically, in vliichuis 5 embodied one lorm-ot' our. improved apparatus Fig. 12 is a side elevation of the drying cylinder \Yllil one form of our improvedapparatus en'rbodicd therein; and Fig. 3 is-an as Fig.- l.

enlz'irged partial section on the same plane There are of course various. types of'drying apparatus ingencral use for carrying" out the same general process of dryingcv'aporated liquids and se 'iarating therefrom materials held in solution or suspension. The accompanying drawings show in a diagram. matical way only one typical drier. to which our improved apparatus hasbecn attached, but it is understood. and it will be'evidentfrom the following t'lcscription. that our improvements are capable of incorporation in carious types of apparatus for this general purpose. i

In Fig. 1 there'is shown a casing 1 of gen- 7 i eral cylindrical form, but providedn'ith an enlarged body portion :2, in which there may be 'snspen'ded or constructed a li'quid-receivingtank 3 for holding the liquid and'matcrial which is to be transferred to the circuinference of a rotary cylinder or drying" rneniber' This latter member is a? plane smooth cylinder closed at eit'herenid and heated internal y by any suitable ineans, usually by mea s of steam introduced at one end and discharged at'the other through trunnion bearings; This cylinder is rotatedat arelatively low speed and at. its bottom dips. into the surface of the liquid held in ithe tank 3, although in some forms of driers this liquid is sprayed against the'surface of the drum at this same'point in its revolution. The cylinder is rotated in the. direction of the arrow shown inFi'g. 1* and on the 'lower left-hand side of the cylinder moved therefrom by any suitable conveying means, such, for example, asthe screw con- 106 veyor 7 shown. .Any suitablemeansmay be employed for lhaintaining liquid in the tank 3 and we have hown a pump 8 coni v filter 11 and the se es water vapor, in the chamber 1 to be condensedand to flow down into the stand, pipe 13, while the air and nected to. the reservoir 9 in the base of the chamber 1 for this purpose.

During the operation of the cylinder at high vacuum is maintained in the chamber 1, this chamberbeing connected by means of a goose-neck condu1t10 with a dust filter 11, which is in tur connected to a separating cylinder 12, w ich opens at its bottom into astand pipe 13, The stand pipe 13v is connected to a suitable water connection, such as a sewer" or well .14, while the upper end of the separating chamber12 is connected to a vacuhin' pump 15 by means of a conduit16. As to the operation of. the vacuum system it is 'suflicient to say that the vacuum is maintained in the drum by the suctionthrough the goose-neck 10, the dust arating chamber 12, ows any vapor, such air drawn from the which latter means a are carried through the other gases, ifany,

harged from thevacuum conduit 16 and dis pump 15.

To operate-efliciently, an apparatus, such "as is diagrammatically shownin the draw-, .ings and briefly explained above, should operate to cause no deposit 11, which is built into the system for removing :any dust or other solid material which.

may by chance he carried over with the evaporated liquid from the chamber 1. If,

action has slowed up at any point, the movement of air and vapor through the goose neck 10 will be correspondmgly lessened v,and any solid material carried in suspension bythe air and vapor,

however, the suction will tend to deposit at this point, and after a relatively. short time will block this passageito such; an extent that the operation of the apparatus mustbe stopped and the goes: neck and other parts opened for clean-' lng. This blocking of; the goose-neck con duit 10 may occur within 'a few hours and necessitates the shutting down of the entire apparatus for cleaning with a consequent considerable loss in time and output.

We have found that the above defects in the apparatus may be entirely remedied by opposing to the discharging vapor and suspended material a curtain or sheet of some vapor such as steam, which willentrain any suspended material from the discharging vapors and carry it to the sides of the conduit 10, and from the walls of this conduit back into the cylinder 1 or into the dustfilter 11. We provide this curtain or sheetxof vapor by interposing a steam pipe 17 in the goose neck 10, the pipe being curved some what. to conformtopthe curvature of the goose neck and extending from the point of connection of the goose neck and the chamber 1 to a point somewhat beyond the at any point in the system, except possibly in the dust filter "and in any event will serve to wash-off -material which is deposited on these parts,

hea ers in all directions from the center toward the walls of the conduit 10, in this Way opposing a curtain of steam of considerable to the passage of any particles of solid matter through this conduit. All of the particles of solid matter which are carried by the length discharge vapor are brought to the walls of the conduit 10 by the action of these jets of steam, and it is immaterial whether the collected matter then falls into the dust filter gr back into the liquid reservoir in the chamer 1. v t I Another defect in the operation ofcdrying apparatus of this general type is that the \knives 5 cannot be made to hug the surface of the cylinder closely enough to prevent the passage of some material between the knife and the cylinder, and. any material which passes by the knife and then falls from the cylinder may deposit on the inner edge of the knife blade on the. side toward the,cylinder and will'eventually' build up" a deposit of such thickness as to prevent the convenient adjustment of the knife and, in

some cases, as to press with considerable force against the drum 0 posite the base of the knife. It has been f dund that this-objection may be entirely avoided by fastenmg a guard plate 20- on the inner side of the knife blade extending over the 'base in which the knife blade is carried, and by extending a conduit'21 for, the full length of these knives, the conduit being provided with openings, which will direct vapor sprayed therethrough toward the bases of the-knives in such a we of any deposits between the knives and adjacent Parts, and the cylinder. The material which may be sent through thepipe 21 may be either steam, water or the liquid contained in the reservoir in the cylinder 1', any

and to, return the same to the liquid voir in the base of the chamber.

It frequently happens that a' deposit forms on the en of the cylinder and this must be either prevented orvremoved. The formation of such deposit may be entirely prevented by directing a jet of steam -or reserother vapor or liquid against the edge or end of the cylinder, as indicated in Fig. 2,

a conduit 23 having its end turned so as to v spray a jet of liquid or vapor at an acute angle against the end 24 of the drum 4 and downwardly, so as to wash any material depositing thereon into the reservoir in the chamber.

The action of the follows :After the liquid has been intro-1 present, apparatus is as; m

as to prevent the formation 7 of the conduit- 10, from which they back into the drying chamber and into the duced into the vacuumchamber and-the tank 3, the pump 15 is started to set up a suction through the apparatus and create a high vacuum in the vacuum chambei 1. The

. drum 4 is rotated and as the drum dips into I the liquid in the tank 3 a thin film-of the solution to he evaporated is spreadover the surface of the heated drum 4" and the driedproduct is scraped therefrom by means otthe knives 5. The vapors from the liquid are carried through the conduit 10and some of the solid material isinevitably carried along with these vapors. The vapor curtain or screen, which .is sprayed from the open ings 18 in the conduit 17 transversely of the enclosing conduit 10, causes the particles of solid matter tobc deposited upon the (vivalls rain liquid in the bottom thereof. The apparatus may of course operate on different kinds of'material, but it has been very successfully '-used in connection with the drying of lime sulphur solutions. r y the methods and apparatus described we have succeeded in avoiding loss of mate'- 'rial 'm-the exhaust vapors,. and what is more important, have effected a great saving in time by preventing formation of objectionable deposits at various points which could only be removed when the apparatus was stopped and opened to workmen, which was in many cases unpleasant and sometimes extremely detrimental to their health on account of the gases arising rial undergoing drying.

Other modes of applying the principle of our invention may be employed instead of said conduit, and

from the matethe steps comprising evaporating a fluid 1n a'vacuum chamber and then removing suspended material from the evolved vapor by subjecting it to the entraining action of a transversely directed vapor screen.

2. In a method of the character described, theisteps com rising evaporatin a fluid, then assing t e evolved vapor tirough a constrlcted passage and removing suspende material from such vapor by sub ecting it in said passage to the entraming. action of a transversely directed vapor screen;

3. In a method of the character described, the steps comprising removing suspended material from evolved vapor by subjecting such Vapor-to the entraining action of a transversely directed vapor screen and then collecting t e entrained material.

' 4. In apparatus of the character described,

the combination of a vacuum drying chamher, a suction conduit leading therefrom, a

perforated pipe extending longitudinally of connections adaptet to supply steam to said pipe so as to dprovidea curtain of water vapor n sai conduit through which the vapors being evacuated from-said chamber have to pass.

Signed by us, this 9th day ofApril. 1918. MARTIN J. OBOYLE. EDWARD C. HOLTON. 

